Reference Guide

Chapter 4 SCSI Commands
SCSI Command Descriptions
DLT-S4 Interface Reference Guide 31
SCSI Command Descriptions 4
The SCSI command descriptions that make up the rest of this chapter
contain detailed information about each command the DLT-S4 tape drive
supports. The SCSI commands are presented in alphabetical order. Fields
common to many of the SCSI commands are not repeated for every
command; instead they are supported as shown in table 14
.
Table 14 Fields Common to
Many SCSI Commands
Throughout this manual, multiple bytes that contain information about
specific command parameters are portrayed as shown in the example of
the Parameter List Length field (bytes 7 to 8) of the
LOG SELECT
command, shown as follows:
This sample indicates that the most significant bit (MSB) of the field is bit
7 of byte 7; the least significant bit is bit 0 of byte 8. The shorthand version
of presentation is used in this manual to save space.
Field Name How the Field is Supported in SCSI Commands
Control All SCSI commands must have a Control byte, which is
implemented as described in SCSI Architecture Model – 3
(SAM–3).
Reserved Reserved bits, fields, bytes, and code values are set aside
for future standardization and must be set to 0. If the drive
receives a command that contains non-zero bits in a
reserved field or a reserved code value, the drive
terminates the command with a CHECK CONDITION
status and the Sense Key is set to ILLEGAL REQUEST.
Bit
Byte
7 6 5 4 3 2 1 0
(Bytes 0 — 6)
7—8
(MSB)
Parameter List Length
(LSB)